@Artemesia: $40 difference for lower TDP and ~10% better performance in the grand scheme of a ~$1300ish (?) build? Totally worth it.
Right now I'm at $1650 rounding up. My budget is about $1600-$1700. I can push that a little farther if I want/need to.
@Artemesia: You will absolutely need a bigger hard drive.
Also, you should just go for the latest, greatest i7 quad core if you're already going for an i7.
And make sure that your RAM is Z77 compatible. I might also suggest upgrading to their top of the line RAM, it's a bit more expensive (like $30) but looks crazy cool.
Here's the rig I'm building for some inspiration, you seem to be going for about the same budget as me.